Fixed incorrect handling of extra mouse buttons in XCB platform plugin.

translateMouseButtons() was only able to correctly handle the left,
right, and mid mouse buttons. Thus, if any buttons outside of those were
pressed, the motion notify event would basically unset the mouse button
mask, leading to a release event being sent instead. Later on, when the
actual release event arrives, that button gets xor'ed into the empty
button mask generating another press, and later another motion event
will generate a release. In the end that means two press-release
sequences are sent for any extra mouse buttons.

Instead of getting the mask of the buttons currently being pressed from
the event, we need to keep track of the mask ourselves.

Task-number: QTBUG-28561
Change-Id: Iaa67e784a13d792deef8fc29dbd5456a5471a861
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Reviewed-by: Rick Stockton <rickstockton@reno-computerhelp.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 10 insertions, 58 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 23e59f0735..05d7dc4da9 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -1464,53 +1464,6 @@ void QXcbWindow::handleUnmapNotifyEvent(const xcb_unmap_notify_event_t *event)
     }
 }
 
-static Qt::MouseButtons translateMouseButtons(int s)
-{
-    Qt::MouseButtons ret = 0;
-    if (s & XCB_BUTTON_MASK_1)
-        ret |= Qt::LeftButton;
-    if (s & XCB_BUTTON_MASK_2)
-        ret |= Qt::MidButton;
-    if (s & XCB_BUTTON_MASK_3)
-        ret |= Qt::RightButton;
-    return ret;
-}
-
-static Qt::MouseButton translateMouseButton(xcb_button_t s)
-{
-    switch (s) {
-    case 1: return Qt::LeftButton;
-    case 2: return Qt::MidButton;
-    case 3: return Qt::RightButton;
-    // Button values 4-7 were already handled as Wheel events, and won't occur here.
-    case 8: return Qt::BackButton;      // Also known as Qt::ExtraButton1
-    case 9: return Qt::ForwardButton;   // Also known as Qt::ExtraButton2
-    case 10: return Qt::ExtraButton3;
-    case 11: return Qt::ExtraButton4;
-    case 12: return Qt::ExtraButton5;
-    case 13: return Qt::ExtraButton6;
-    case 14: return Qt::ExtraButton7;
-    case 15: return Qt::ExtraButton8;
-    case 16: return Qt::ExtraButton9;
-    case 17: return Qt::ExtraButton10;
-    case 18: return Qt::ExtraButton11;
-    case 19: return Qt::ExtraButton12;
-    case 20: return Qt::ExtraButton13;
-    case 21: return Qt::ExtraButton14;
-    case 22: return Qt::ExtraButton15;
-    case 23: return Qt::ExtraButton16;
-    case 24: return Qt::ExtraButton17;
-    case 25: return Qt::ExtraButton18;
-    case 26: return Qt::ExtraButton19;
-    case 27: return Qt::ExtraButton20;
-    case 28: return Qt::ExtraButton21;
-    case 29: return Qt::ExtraButton22;
-    case 30: return Qt::ExtraButton23;
-    case 31: return Qt::ExtraButton24;
-    default: return Qt::NoButton;
-    }
-}
-
 void QXcbWindow::handleButtonPressEvent(const xcb_button_press_event_t *event)
 {
     updateNetWmUserTime(event->time);
@@ -1532,7 +1485,7 @@ void QXcbWindow::handleButtonPressEvent(const xcb_button_press_event_t *event)
         return;
     }
 
-    handleMouseEvent(event->detail, event->state, event->time, local, global, modifiers);
+    handleMouseEvent(event->time, local, global, modifiers);
 }
 
 void QXcbWindow::handleButtonReleaseEvent(const xcb_button_release_event_t *event)
@@ -1541,7 +1494,12 @@ void QXcbWindow::handleButtonReleaseEvent(const xcb_button_release_event_t *even
     QPoint global(event->root_x, event->root_y);
     Qt::KeyboardModifiers modifiers = connection()->keyboard()->translateModifiers(event->state);
 
-    handleMouseEvent(event->detail, event->state, event->time, local, global, modifiers);
+    if (event->detail >= 4 && event->detail <= 7) {
+        // mouse wheel, handled in handleButtonPressEvent()
+        return;
+    }
+
+    handleMouseEvent(event->time, local, global, modifiers);
 }
 
 void QXcbWindow::handleMotionNotifyEvent(const xcb_motion_notify_event_t *event)
@@ -1550,19 +1508,13 @@ void QXcbWindow::handleMotionNotifyEvent(const xcb_motion_notify_event_t *event)
     QPoint global(event->root_x, event->root_y);
     Qt::KeyboardModifiers modifiers = connection()->keyboard()->translateModifiers(event->state);
 
-    handleMouseEvent(event->detail, event->state, event->time, local, global, modifiers);
+    handleMouseEvent(event->time, local, global, modifiers);
 }
 
-void QXcbWindow::handleMouseEvent(xcb_button_t detail, uint16_t state, xcb_timestamp_t time, const QPoint &local, const QPoint &global, Qt::KeyboardModifiers modifiers)
+void QXcbWindow::handleMouseEvent(xcb_timestamp_t time, const QPoint &local, const QPoint &global, Qt::KeyboardModifiers modifiers)
 {
     connection()->setTime(time);
-
-    Qt::MouseButtons buttons = translateMouseButtons(state);
-    Qt::MouseButton button = translateMouseButton(detail);
-
-    buttons ^= button; // X event uses state *before*, Qt uses state *after*
-
-    QWindowSystemInterface::handleMouseEvent(window(), time, local, global, buttons, modifiers);
+    QWindowSystemInterface::handleMouseEvent(window(), time, local, global, connection()->buttons(), modifiers);
 }
 
 class EnterEventChecker